I was curious about the whole DCL concern about Monkey and P kissing, too. A few of you commented here and on plurk that there was nothing wrong with it — it’s cute. And I agree, it is cute when kids hug and kiss. Kids are affectionate, and they model adult behavior. Monkey knows Mommy and Daddy love each other; Mommy and Daddy kiss each other on the lips; Monkey loves P; she and P can kiss on the lips. Elementary!
Although there is nothing inherently sexual in kids under, say, ten kissing — even on the lips — or holding hands, we live in a weird society. And while I wouldn’t condone going this far, I think daycares and schools are within their rights setting rules for appropriate touching. After all, if the child being pinched doesn’t want to be pinched and asks the pincher to stop, and the pincher doesn’t, then it is harassment. Albeit not sexual harassment.
While I feel that telling Monkey that she is not old enough to kiss boys (or anyone outside of our family) on the lips is a good strategy in this case, I think there are other appropriate boundaries to set. For example, I would tell Monkey to ask permission before holding someone’s hand. That would be respectful. I would hope that the little boy in question with Monkey at least said, “Hey, I really like you. Want to kiss?” In that case, I can’t see Monkey saying, “Heck no!” Especially if the boy was cute. (Monkey, she likes the boys.) I would hope that if someone forcefully kissed Monkey or grabbed her hand, she would have the confidence to pull away, or say, “no” or “stop”.
But I’m not going to use terms like sexual harassment or inappropriate touching or even “mouth kissing” with Monkey. She’s four, as she points out several times a day. Not eleven.
I don’t want to go giving her ideas.
Red Pen Mama 
Agreed.
I understand setting boundaries, because you don’t want to have one kid who is a little more touchy feely making another kid uncomfortable. I think asking permission is a wonderful way to go about it.
It’s so cute that Monkey already likes boys. And I still think it’s cute that they were kissing because, like you said, it’s *not* sexual: it means they are friends!